Protein kinase C (“PKC”) is a key enzyme in signal transduction involved in a variety of cellular functions, including cell growth, regulation of gene expression, and ion channel activity. The PKC family of isozymes includes at least 11 different protein kinases that can be divided into at least three subfamilies based on their homology and sensitivity to activators. Each isozyme includes a number of homologous (“conserved” or “C”) domains interspersed with isozyme-unique (“variable” or “V”) domains. Members of the “classical” or “cPKC” subfamily, PKC α, βi, βii and γ, contain four homologous domains (C1, C2, C3 and C4) and require calcium, phosphatidylserine, and diacylglycerol or phorbol esters for activation. Members of the “novel” or “nPKC” subfamily, PKC δ, ε, η and θ, lack the C2 homologous domain and do not require calcium for activation. Finally, members of the “atypical” or “αPKC” subfamily, PKC ζ and λ/i, lack both the C2 and one-half of the C1 homologous domains and are insensitive to diacylglycerol, phorbol esters and calcium.